Heat accumulator



Marel. 2o, .1934. POHL'H HEATl AccUMuLA'ron Filemay 17. leso 2 Sheets-Sheet 2 f f f l Zone no? W f j?? .Ve/7 fans f f Haras Po/zl [Zzzard Pa? Patented Mar. 20, 1934 NT oiFFicE 1,951,579 HEAT ACCUMULATOR Hans Pohl, Burgbrohl,

and Eduard Pohl, Rhondorf, GermanyrsaidHans Pohl assigner to firm Steinund Thonindustriegesellschaft Brohlthal, Burgbrohl, Germany ApplicationMay 17, 1930, Serial No. 453,309

In Germany January 3, 1928 l 4 Claims.

The present. invention relates to the construc tion of heat'accumulators of which the checker work is divided into various'superposed zones which follow one another in the arrangement of the iiow of` the gases.

The state of the art of blast furnace mouth gas purification enables the blast furnace engineer, when erectinggheat accumulators to reduce the width of the passages-and the thickness of the wallsA considerably further than was hitherto possible, as there is no longer any liability to the I easy clogging-up of small passage areas by the thoroughly cleaned gases which are available at the present time. y

In accordance with the reduction in volume of the heating gases'as a result of the continued drops in temperature the heat accumula'tors are provided with passages which become smaller towards the bottom.' In the. lower portions of the heat accumulators it is of advantage, as regards a good economy in heat and provided theta thoroughly puried gas is' available, to usepassages of small cross sectional area and stones of small thickness.

the heat accumulator from simple thin rectangular plates or single passage stone, this would require comparatively-`high wages for erection and the rigidity of the entire checker Work would become entirely. insuflicient as the plates or stones would have to be made of very small size and would thus also have a very low resistance mo'- ment. A

Stones having a number of passages are in use for heat accumulators. `'Ihese stones, however, have the disadvantage that on the further reduction of the cross section of the passages the stones become too small and leadto diiculties v'ln construction. If, however; a large number of 40 small passages are Aassembled in large stones then I both at the edge of the stone and also when assembling a number of similar stones unequal wall thicknesses are obtained. Such stones when erected vertically with stones having thesame surface area, but which have smaller or larger passages, have the disadvantage that these pasi sages are wholly or partly covered. l

. The objectl of the present inventionds to obtain a hightechnical effect by the provision of larger vertical heating surfaces with a favourable ratioof the free passage area and the weight of 4the stoneand, by the usev of stones of predetermined shape, to eliminate retardingv resistances to ow andto obtain absolutely uniform passages throughout the separate layers, substantially the same total cross section of the passages throughA the entire checker work, and at the sama:l time If itwals desired to form this lower portion of- Figure 2 is a vertical section of the checker 1 work to a larger scale. A

Figures 3 to 9 show plans of the various types of stones which are used in the ,superposed zones in order to enable the resultof. the-invention to be obtained. l I

Figures 10 to 13 show the ratio of the internal widths of the passages in the various-zones.

A Ais the complete heat' accumulator, B the combustion shaft for the rising gases, C the cupola and D the checker work in which the gases pass downwardly. The uppermost zone I of the checker work consistsv of stones e 4with passages in the form of Laval' no zzles as shown in plan in Figure 3.V The term Laval nozzle as used in this specification and claims means an orice or inlet of a passage formed inKsuch a. manner that in the direction of flow of the fluid to be transported the cross-section of the passage is first contracted or'narrowed by rounding oi the 'edge of the surrounding wall, and then again enlarged, (see the three passages of the uppermost layer in Figure 2).v A characteristic feature of a Laval nozzle" isthat theV transformation of the energy of a 'iiowing liquid is effected therein without a loss of energy. There then follow layers f (Figure 4) of a checker work formed by the assemblage of rectangular rounded plates of the same thickness of wall with Vsc uare passages. There then follows a layer y (Figure 5) of stones with passages therein for converting the increased pressure into velocity and then a further checker work f as above described vformed of rectangular rounded plates. For the purpose ol conducting `the gases to the succeeding checker work having smaller passages there are `provided stones h'having passagesV in the form of t of gases therethrough is effected substantially without loss. v

There now follows a Zone II formed of stones indicated at i, f, g, f, h, which in the same area have four times as many passages as the stones in Zone I. 'Ihe last layer of stones h in the Zone I is mounted on a layer of stones i (Figure '7) having passages in the form of Laval nozzles which very effectively lock the transitory stones h by the raised crosses in the form of Laval nozzles provided thereon.

There now follows a Zone III formed of stones i, i and nally transitory stones h which in the same area have sixteen timesas many passages as the corresponding stones of Zone I. The stones i are similar to the stones i in Zone II. whilst the stones i' have smooth passages. At about the middle the Zone III has stones. with passages in the form of Laval nozzles, these passages each extending over four passages in the adjacent stones, whereby in the case of clogging up` of the separate passages by ashes or the closing of the separate passages by an incorrect positioning of the adjacent stone, the continuation of the closed passage is not placed out of operation.

From the Zone III there extends a Zone IV of which the construction is similar to the Zone III, but of which stones the same area contains sixtyfour times as many passages as the stones in Zone 1.

As a closure and for supporting the entire checker work there is provided a cast iron grate l having passages in the form of Laval nozzles.

The fundamental idea of the invention resides therein that the checker work and the division thereof into separate zones is constructed according to a mathematically accurate centre line varea system arrangement. In the first zone a indicates the distance between the centres of two oppositely disposed walls of a stone, b the internal width of the passages, and c the thickness of the Walls whilst the mathematical' relations in the separate z'onesare according to the following equations:

Zone I. a.a :a2 (Figure 10).

Zone II. 4=a2 (Figure 11).

Zone III. 161-6=a2 (Figure 12).

.v 2 Zone IV. 64.-4=a2 (Figure 13) and so on.

This shows that the upper Zone I having an area a2 (Figure 10) is divided into four squares each having an area of in Zone II. Zone III is obtained by dividing .Zone I into sixteen equal squares each of an area improvem Finally there comes Zone IV, wherein each passage in Zone I is divided into sixty-four equal -squares leach having an area of or each of the sixteen squares of Zone, III having an area of is divided into four equal squares each having an l area of The determination of the internal width of the square passage in the separate zonesy is determined according to the following equations:

Zone I.

Zone II.

in which the value of c (thickness of the wall) may vary. Finally it is also necessary to consider the thickness of the walls and in this connection the following is generally usual.

The quadratic centre 'arrangement resulting therefrom for the passage chain is the essential feature of the new arrangement. In this centre arrangement there may also be included besides square passages, round, polygonal or other passages.

By the mathematically accurate quadratic division and subdivision of the structure there are obtained as a 'result of this basis of construction the following:

1. In each zone there is throughout exactly the same total passage area.

2. In each zone there is throughout exactly the same total thickness of stone.

3. In all the zones there is the same weight Aper cubic meter of constructional area.

4. In all the zones there is the same free passage area per square meter of constructional area.

5. There is no overlapping as the passage of the first zone is divided into four square passagesv in the second zone, into sixteen square passages in the third zone and nally into sixty-four square passages inthe fourth -zone (Figures 10 to 13).

For obtaining the advantages set out above the heat acc ulator is provided with the following 1. The upper layer of stones e of the checker work is provided with passages in the form of Laval nozzles for the purpose of converting the pressure energy existing in the upper passages into velocity energy. l

2. For eliminating deviations which unavoidably occur when Verecting an ordinary checker work by reasonv of non-uniform rectangular stones, thev vstones for the checker work are rounded off or inclined at' the edges, so as to form passages-which are enlarged in the mannerofnozzles.

3. The succeeding layer of stones g having passages in the .form of nozzles (Figure must fulfil the following condition:After the pressure energy of the gases of combustion in the upper stones having passages in the form of Laval nozzles has been converted intoenergy of ilow the velocity at which the gases must flow through will decrease very rapidly by reason of the long path. If stoneshaving passages inthe form oi nozzles as shown in Figure 5 are inserted at suitable intervals and provision is made for the reduction in volume of the heating gases by dimensioning the cross sectional area of the passages for the purpose in view, then it is possible in accordancewith the invention to again increase the velocity of the heating gases which ,has become insumcientin the"fpassages and. substantially improve the` heat accumulation.

d. For obtaining a passage of gas from one zone of the checker work to the next, which is asf-free as possible from disturbance, stones h having passages in the form of Laval nozzles are provided, which connect a single passage located above them with four separate `smaller passageslooated underneath them, and having the sametotal area whilst further passage stones a1 connect together inthe lower zones any suitable number of passages in such a manner that in the case of clogging up of the' separate passages by means of ashes, incorrect positioning or collapsing, the passages in question arevnot rendered inoperative along their whole length. In

y this 'case the bridged passages of all the lower stones ofthe checker work are inthe form of Inval nozzles i so as to avoid any resistance to flow. Y

5. The lowest zones of the heat accumulator are constructed from separate novel stones i.' for forming checker work whichwhilst having the same thickness of wall possess a maximum heating surface and weight of stone with. the highest rigidity. These stones are of such a shape as though square pipes had been formed integral at their side surfaces and then divided intosuitable sections by diagonal cuts obycuts through passages at distances which a. e a multiple of the Wixlth of the passage and the thickness of the wa Briey stated the followingimprovements and advantages are obtained from the invention.

` (a) Conversion of the pressurel` energy exist-f ing .above the uppermost passage zone into energy of flow.

(b) .The inaccuracies in'the assemblage of an y ordinary checker'work are eliminated by. rounding off or incliningthe edges of the stones thus also obvlating (':ontractions and accumulations.

(c) The stoneA g with the passages in the form of nozzles increasesfthe velocity of the gases which has' become insuflicient and may bridge overl anumber of vpassages in-the lower zones.

' layer.V

zones of the checker work the existing Velocity is converted inthe enlarged passages in the stones into pressure and when entering the smaller passages is again converted into velocity by nozzles. v

e (e) The new stone i' is provided in cross section with a suitable number of equally large passages having all the same thickness of wall between the heating surfaces and may be made in the form of a suitably large block even when provided with the smallest passages.

Y (f) The square shape and the square centre arrangement of the .passages when erecting multiapertured stones in a checker work formed ci a number of stones enables inexpensive checker plates of known construction to be used inthe upper zones and thus reduces thel cost of the complete checker work.

(g) The provision ofthe cast iron supporting grate with passages in the form of Laval nozzles.

The cleaning of a heat accumulator constructed by means -of stones for the checker work in accordance with the present invention can be effected easily in the known manner, the `checker work is extremely certain in operation and af fords the maximum thermal efficiency.

1. In a heat accumulator of which the checker work is divided into various superposed zones, a layer formed of stones with apertures the cross section of which substantially follows the converging sides of anisosce'les trapezoid continued adjacent the shorter one of the parallel sides of the said trapezoid by 'two divergent quartersy of a circle.

2. In a heat accumulator of which the checker work is divided into various superposed zones, al

layer Aformed of stones having inlet and outlet openings the cross section of which substantially follows the converging sides of an isosceles trapezoid continued adjacent the shorter one of the parallel sides of the said trapezoid by two divergent quarters of a circle.`

E20 3. In a heat accumulator of which the checker work is divided into various superposed zones,

'a layer adjacent to thecupola formed of stones with apertures the' cross section of which substantially follows the converging sides of an isosceles trapezoid continued adjacent the shorter one of the parallel sides of the said trapezoid by two divergent quarters of a circle.

4. In a heat accumulator of which the checker work is divided into various superposed zones,

passages .extending through thesaid checkerwork and decreasing in diameter from one zone to the next lower one in the ratio of 2: 1,the stones of each layer being arranged in such a. manner 'that the centers ofthe passages coincide with the ,intersections of equidistant lines crossing atright angle, and the layers being superposed in such a manner that each passage of one layer is continued by four passages of the subsequent HANS Pom.. EDUARD Pom...- 

